Question

The volume and the total surface area of a solid right pyramid of height $4cm$, and square base of side $6cm$.

• A. $24cc,86sq.cm.$
• B. $48cc.90sq.cm.$
• C. $24cc,80sq.cm.$
• D. $48cc,96sq.cm.$

Answer 1

The correct option is D $48cc,96sq.cm.$

Volume of pyramid $=\frac{1}{3}\times basearea\times height=\frac{1}{3}\times 6\times 6\times 4=48cc$
$\Rightarrow$ Length of slant face $=\sqrt{4^2+3^2}=5cm.$
Area of each slant face $=\frac{1}{2}\times 5\times 6=15sq.cm.$
Area of base $=6\times 6sq.cm.=36sq.cm.$
$\Rightarrow$ Total surface area $=4\left(15\right)+36sq.cm.=96sq.cm.$